1. Technical Field
The present invention relates to an image processing device, an imaging device, an image processing method, and a computer readable medium.
2. Background Art
Digital cameras are widely known that are provided with autofocus, in which phase difference detection methods and contrast detection methods are employed, and also what is referred to as a manual focus mode, in which a user can manually perform focus adjustment.
Digital cameras including a manual focus mode are known in which a reflex mirror is provided to enable focus adjustment while checking a subject-image, and a method is utilized in which a split microprism screen is employed to display the phase difference visually. Utilization of a method in which contrast is checked visually is also known.
However, in digital cameras with the reflex mirror omitted that have become prevalent in recent years, since there is no reflex mirror, there is no method to check the subject-image while displaying the phase difference, and contrast detection methods have had to be relied on. However, in such cases, contrast cannot be displayed at a resolution greater than that of a display device, such as a Liquid Crystal Display (LCD), requiring adoption of methods such as enlarging a portion for display.
In recent years, therefore, a split-image is displayed within a live-view image (also referred to as a through image), so as to make the work of focusing on the subject-image easier for an operator when in manual focus mode. Split-image refers to a divided image in which, for example, a display region has been divided into plural sections (such as each image divided in the up-down direction), and in which displacement is imparted in the parallax generation direction (such as the left-right direction) according to focus misalignment, and is a divided image in which the displacement in the parallax generation direction disappears in an in-focus state. The operator (such as a photographer) operates a manual focus ring (hereafter referred to as a “focus ring”) to match the focus so that displacement of the split-image (such as each image divided in the up-down direction) is removed.
In the imaging device described in JP-A No. 2009-147665 (referred to below as “Patent Document 1”), out of light rays from an imaging optical system, a first subject-image and a second subject-image formed by light rays divided by a pupil divider are photoelectrically converted to generate a first image and a second image, respectively. The first and the second images are employed to generate a split-image, and a third subject-image formed by the light rays not divided by the pupil divider is photoelectrically converted to generate a third image. The third image is displayed on a display section and the generated split-image is displayed inside the third image, and color data extracted from the third image is applied to the split-image. By applying color data extracted from the third image to the split-image in this way, excellent visibility of the split-image can be achieved.
An imaging device described in JP-A No. H07-15648 (referred to below as Patent Document 2) includes a manual focus function, and determines the movement speed of a focusing lens that is moveable along the optical axis direction according to the subject depth of field.
An imaging device described in JP-A No. 2007-108584 (referred to below as Patent Document 3) includes a focal point adjustment mechanism that, coupled to manual operation, adjusts to move a focusing lens to the in-focus position. The focal point adjustment mechanism in this imaging device controls such that the movement speed of the focusing lens is slow with respect to an image pick-up device in cases in which a focus evaluation value of an imaging lens is high, and the movement speed of the focusing lens is fast in cases in which the focus evaluation value is low.